heavy rail

The term heavy rail is often used for regular railways, to distinguish from systems such as trams, light rail, medium capacity system, and metro.Heavy rail typically refers to the standard inter-city rail network, which is built to be robust enough for heavy and high-speed trains, including freight trains, and long distance and high speed passenger trains. For these reasons, curves and slopes are gentle. Heavy rail is almost always built on its own dedicated right-of-way and is separate from road traffic.
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High-speed, passenger rail cars operating singly or in trains of two or more cars on fixed rails in separate rights-of-way from which all other vehicular and foot traffic is excluded. (FTA1)

An electric railway with the capacity for a "heavy volume" of traffic and characterized by exclusive rights-of-way, multi-car trains, high speed and rapid acceleration, sophisticated signaling, and high platform loading. (APTA1)

Transit service using rail cars powered by electricity which is usually drawn from a third rail and usually operated on exclusive rights-of-way. It generally uses longer trains and has longer spacing between stations than light rail. (FTA2)